Electric discharge device



Jan. 9, 1934. A, E McLEOD 1,942,824

ELECTRIC DISCHARGE DEVICE Filed April 14. 1932 Fzg. 4. 7

\ 8' Fig.5. 7

AVTOF/VE/ Patented Jan. 9, 1934 'uNiTEo STATES ELECTRIC DISCHARGE DEVICEAlbert Edward McLeod, Kenton, England, as-

signor to The M-O Valve Company Limited,

London, England Application April 14', 1932, Serial No. 605,140, and inGreat Britain May 29, 1931 6 Claims.

This invention relates to methods of supporting wires, such as electrodesupporting wires, in electric discharge devices.

I "In the manufacture of electric discharge devices a rigid and yetinsulating connection has often to be made between wires. A common wayof making such a connection is to embed the wires in a bead of glass orsimilar material. The

object of this invention is to provide an improved l0 substitute forsuch beads.

In an insulating support for wires in electric discharge devices,according to the present invention, the wires are rigidly held correctlyspaced by a metal member which is pressed on to the wires with a stripof thin flexible insulating material interposed between the wires andthe member so that the member and strip are deformed by the wires.Preferably the thin flexible insulating material is mica and the metalmemher is made of steel.

A metal member and a strip of thin flexible insulating material may bearranged on each side of the wires and the two members may be pressedtogether to press the wires into both members, furthermore the twomembers may comprise parts of a continuous metal strip or plate.

The insulating support may conveniently be used for supporting theelectrode supporting wires of an electric discharge device.

The invention will now be described by way of example, with reference tothe accompanying drawing.

Figure 1 is a side elevation of a broadcast receiving valve showing theinsulating support applied to the spacing apart and supporting of theinternal electrode supporting wires. Figures 2 and 3 are a plan and sideelevation respectively of the support on an enlarged scale. Figures 4,5, 6 and 7 show various stages in one method of manufacturing thesupport shown in the previous figures. Figure 8 is a plan of a bottomdie which may be used in forming the support and Figure 9 is a sectionon the line 99 of Figure 8, the corresponding top die being shown inposition above the bottom die. Figures 10 and I1 show a modifiedconstruction.

With reference to Figure 1 the valve has an envelope which comprises aglass portion 1 and a copper portion 2, the latter portion forming theanode of the valve. The internal electrodes are arranged within theanode 2 and are mounted on electrode supporting wires 3 held suitablyspaced apart by an insulating support 4. The internal electrodes andsupporting wires are assembled as a single unit before insertion intothe are clamped, a strip of mica 8 being interposed between each member7 and-the wires 3. The two members '7 form parts of a single metal stripin the construction shown, but in some constructions two separatemembers may be used.

Onemethodof constructing the support may be followed from Figures 4, 5,6 and '7. The strip '7 is originally in the form of an annulus, Figure 4being a plan view of such annulus and '75 Figure 5 a side elevation. Theannulus is deformed, preferably by inserting a suitably shaped mandreland applying external pressure, to" form an elongated sleeve as shown inplan view in Figure 6. The two mica strips 8 are placed within thesleeve 7 and the five ele'ctrode'supporting wires 3 are inserted intothe sleeve between the strips 8 as shown in Figure 7; preferably atthisstage the electrodes'have been attached to the wires 3. The annulus 7may be formed by cut- '85 ting a section from a steel tube, orby'bending a strip round in a circle and joining the two ends, forexample by welding. In the latter case however the sleeve shown inFigure 6 may be formed direct. The wires 3 are now suitably spaced apartwithin the sleeve '7 and the sleeve is pressed between two dies so thatthe wires are pressed into the opposite sides'of the sleeve '7 which aredeformed by the wires, at the same time the wires 3 are insulated fromone another and from the sleeve 7 by the mica strips 8, which are alsodeformed by the wires.

Two dies suitable for performing this last operation are shown inFigures 8 and 9 and these, will now be described. The bottom diecomprises a solid block of metal in which are formed a small channel 10,in which the top die 11 is adapted to fit, and a larger cross channel12, which is adapted to receive the wires 3. At each end of 5 thechannel 12 are provided two combs the teeth 13 of which serve to spacethe wires 3 the correct distance apart. The part of the bottom die whichis common to the two channels 10 and 12 is formed with five troughs 14corresponding to the fivewires 3. The top die 11 is similarly formedwith five troughs 15.

When the wires 3 have been inserted in the sleeve 7 between the micastrips 8, the sleeve 7 is arranged in the channel 10 of the bottom dieso that the projecting wires 3 extend along the channel 12 and arespaced apart correctly by the teeth 13, a tooth 13 being arrangedbetween each pair of adjacent wires. The top die 11 is now lowered intoposition in the channel 10 and the two dies pressed firmly together. Theresult is that the sides of the sleeve are pressed onto the wires 3,which thereby deform the sleeve by being pressed into it and forcingparts of the sleeve into the troughs 14 and 15, and a support as shownin Figures 2 and 3 is formed.

In the modified construction shown in Figures 10 and 11 a longrectangular hole 18 is formed in a flat rectangular metal plate as shownin Figure 10. The plate is then folded about the line 17 to the formshown in Figure 11, which is a section on the line 16i6 of Figure 10 ofthe plate after it has been folded, so that the parts of the plate onthe two sides of the line 17 are arranged opposite one another andconstitute the two members 7. The wires 3 are now passed through thehole 18, suitably spaced apart with the mica strips 8 arranged onopposite sides of the wires as shown and the two members 7 are pressedtogether against the wires 3 between two dies as in the previousconstruction. Instead of forming a single hole 18 to take all the wires3 separate holes may be formed to take one or more of the wires.

If desired the support may be formed from two separate members 7 heldtogether in any suitable manner, for example by bending the end of onemember over the end of the other at the same time as the members arepressed together. Alternatively the two members may form the two arms ofa U shaped member, which arms may be pressed together to grip the wires3.

Although mild steel has been mentioned as a suitable metal to use forthe members there are many others which may be used, for examplecopper-nickel alloys, copper, or nickel.

I claim:-

1. In the manufacture of an electric discharge device a method offorming an insulating sup port for rigidly holding wires correctlyspaced apart which comprises arranging two strips of thin flexibleinsulating material and the spaced wires within an elongated metalsleeve, the wires being arranged between the two strips, and applyingpressure to the two opposite sides of the metal sleeve so as to deformthe latter and press the strips against the Wires whereby the Wires areheld in proper spaced relation.

2. In the manufacture of an electric discharge device themethod offorming an insulating support for rigidly holding wires correctly spacedapart which comprises arranging a strip of metal around the spacedwires, arranging strips of mica to insulate the wires from the metalstrip and then applying pressure to the metal strip so as to force themica against the wires and deform the metal strip and the mica strips soas to hold the wires in proper spaced relation.

3. In the manufacture of an electric discharge device a method offorming an insulating support for rigidly holding wires correctly spacedapart which comprises arranging the wires in spaced relation with ametal member within a mold, placing thin flexible insulating materialbetween the spaced wires and the metal member, then applying pressure tothe metal member to deform both the insulating strip and the metalmember over the wires and form grooves into which the wires are forced.

4. In the manufacture of an electric discharge device a method offorming an insulating support for rigidly holding wires correctly spacedapart which comprises arranging a metal member with opposed portions onopposite sides of the Wires and placing thin flexible insulatingmaterial on each side of the spaced wires between said opposed portionof said member and the wires and then applying pressure to the opposedportions of the metal member so as to force the insulating material andthe opposed portions of said metal member inward to permanently deformthe metal member around the wires and corrugate the insulating strips tothereby secure the wires in properly spaced relation.

5. In the manufacture of an electric discharge device a method offorming an insulating support for rigidly holding wires correctly spacedapart which comprises folding a metal plate formed with a hole about afold-line passing through the hole, arranging the wires between twostrips of thin flexible insulating material, inserting the wires and thestrips of insulating material between the oppositely disposed parts ofthe plate on the two sides of the fold-line so that at least one of thewires passes through the hole in the plate, and then applying pressureto said oppositely disposed parts so as to force them together and pressthe strips against the Wires.

6. An electric discharge device comprising a plurality of electrodesupporting wires arranged in a row, strips of thin flexible non-adhesiveinsulating material arranged on opposite sides of the row of wires, thestrips being corrugated to form opposite grooves into which the wiresfit and a single metal member with opposed portions similarly corrugatedand arranged to closely embrace the insulating strips on opposite sidesof the wires so as to resiliently hold the wires firmly in the grooves,correctly spaced apart and properly insulated. I

ALBERT EDWARD McLEOD.

